If you have a few backyard does that you enjoy as
a hobby, with little concern for genetic improvements
of their offspring, then artificial insemination (AI)
is probably not for you, assuming a suitable buck
can be located for servicing the does. The expense
of purchasing the necessary equipment and learning
to do AI are likely not worthwhile. However, if there
is an experienced inseminator in the area who is willing
to work with your goats, then this may prove to be
a viable alternative and certainly is much simpler
than hauling your does in heat to the buck's home.
2. AI has some key advantages
over natural breeding.
1) It eliminates the necessity of keeping one or several
bucks on the farm (depending on herd size). Costs
of feeding, housing, separate fencing and labor are
eliminated. However, heat detection may be more difficult
in the absence of a buck.
2) AI can increase the rate of genetic improvement
in an herd, as long as superior bucks are consistently
selected. In natural service, the prospective breeder
has only the buck's pedigree to rely on, whereas AI
bucks should be progeny tested for their transmitting
ability of milk and fat percentage, weight gain, type
conformation, etc.
3) AI allows breeding of different portions of the
herd to different bucks. Young does may be bred to
not yet proven but high potential bucks, while the
majority of the herd can be bred to proven high quality
bucks.
4) AI permits breeding of many does on one day when
synchronization is practiced. No long drives to top
bucks are involved.
5) The danger of transmission of diseases or parasites
is greatly reduced. (The transmission of diseases
through frozen semen needs further study.)
6) The time of breeding can be more carefully regulated,
and the owner knows exactly when the doe was bred,
as opposed to pasture servicing by a buck that is
allowed to run with the herd.
7) AI induces good recordkeeping of dates of heat,
breeding, pedigrees, etc. This will aid in herd improvements
and enable the owner to make better culling decisions.
3. Once the decision to use AI
has been made, the next step is to determine whether
to do the inseminating yourself or pay someone else
to do it. If there are only a few does in your herd,
and an experienced inseminator of goats is available,
then it may be more practical to pay to have the service
done. However, if the number of does in the herd is
rather large, or an experienced inseminator is nowhere
to be found, then its probably time to learn how to
practice AI techniques yourself.
4. AI technicians of the cattle
industry may not necessarily be of much help when
it comes to inseminating goats, for the modern method
of inseminating cattle (rectal palpation) differs
from that of breeding goats (speculum method) considerably.
The speculum was used on cattle early in AI history,
and some cattle inseminators may be capable of teaching
goat insemination.
5. The cost of getting started
in AI, not including semen purchases, will generally
run around $500, of which $400 to $450 is tied up
in the liquid nitrogen tank, which is necessary for
storing semen any length of time. Temperatures must
be kept at -320F (-196C) for sperm survival to be
maximized at breeding time. It may be possible to
share the cost of the tank with neighboring goat owners
or dairy farmers, thus alleviating some initial costs
of an AI program.
6. If AI is to be used with any
hope of achieving a good level of success must be
known and well understood by the prospective inseminator.
1) basic knowledge of the doe's reproductive organs
and their functions;
2) understanding of storage and handling of semen;
3) ability to use, in a proper and sanitary manner,
the equipment required for inseminating goats;
4) ability to accurately detect heat at an early stage;
5) necessity of keeping accurate, up to date records
of heat cycles, breeding, kidding, reproductive problems,
treatments, and any other pertinent information that
may reflect on the goat's reproductive patterns.
7. Reproductive Organs and Functions
The two ovaries are the sites of egg formation. They
produce estrogens and progesterone, and as such are
determining factors of heat cycle, ovulation and pregnancy.
Basically the estrus (heat) cycle in goats operates
as follows:
1) Proestrus is the time of follicle growth. As an
egg (ovum) begins to mature in an ovary, it becomes
surrounded by a fluid filled sac on the outside of
the ovary, much like a blister forms on the skin.
This growth is accompanied by increasing levels of
estrogen in the blood.
2) Estrus - As estrogen levels peak, the doe will
come into heat. This can be observed by changes in
behavior (increased bleating and restlessness), willingness
to be bred, and the swelling of the external genital
area. The period of ''standing heat'' (acceptance
of the buck) will generally last for 24 to 36 hours.
3) Ovulation, or the release of the egg, is accomplished
by the rupturing of the follicle, expelling the egg
from the ovary, and receiving it into the oviduct
via the fimbria funnel. This occurs very near, or
soon after, the end of standing heat (6 hours before
to 12 hours after). Egg life is 12 to 24 hours, while
the sperm lasts 24 to 48 hours.
4) Metaestrus - in this stage, the ruptured follicle
is undergoing cellular differentation to form a functionally
important tissue mass, the corpus luteum (yellow body).
This structure is responsible for the secretion of
progesterone, a hormone which prevents the development
of another follicle and prepares the uterus to receive
a fertilized egg.
5) Diestrus - is the longest period of the estrous
cycle in does. During this period of corpus luteum
influence, two events may happen:
a) if fertilization of the egg occurred, the corpus
luteum will persist for the entire gestation period,
preventing follicular develop ment and keeping estrogen
levels low.
b) if no fertilization took place, the progesterone
secretions of the corpus luteum gradually lessen,
allowing a new cycle of follicular development to
begin, with a corresponding increase in estrogen levels.
The length of time required for one estrous cycle
without fertilization, ranges from 17 to 24 days in
goats, with the majority taking 21 days. Shorter cycles
are not uncommon (5-10 days).
8. The egg, after being expelled
from the ovary, passes into the oviduct via the infundibulum,
and toward the cornua (horns) of the uterus. This
movement is produced by wave-like motions of the ciliated
(hair-like projections) cells of the oviduct. Sperm
and eggs meet in the oviduct and fertilization occurs
in the middle to upper one third of the duct.
9. The egg continues into the
horn of the uterus, where, if it has been fertilized
and undergone several cellular divisions, it will
become attached to the uterine wall. If no fertilization
has occurred, the egg will degenerate and the cycle
goes on.
10. The cervix of the uterus
plays a key role in artificial insemination, as it
is the external entrance to the uterus which must
be located and penetrated with the inseminating instrument.
The cervix is normally tightly closed, except during
periods of heat or kidding. Semen is deposited on
the vaginal side of the cervix in natural services,
but AI requires the deposition of semen in the uterine
side of the cervix. This is because of the greatly
reduced volume of semen that is used in AI. If the
0.5 to 1 cc of semen in AI were deposited on the vaginal
side of the cervix, there is a good chance that none
of the sperm would reach the egg.
11. The vagina serves as the
connecting tube between the uterus and the outside
opening, the vulva. It is part of the birth canal,
and also contains the urethral opening, from which
urine will pass during emptying of the bladder.
12. Purchase and Preparation
of Semen In most cases, the inseminator will acquire
the semen needed by direct purchase from a commercial
operation, in which case it will be shipped to the
inseminator. It is of the greatest importance that
the semen be transferred to permanent storage (the
liquid nitrogen tank) without exposing it to anything
approaching air temperature. Generally, this means
transferring the container element which houses the
semen directly to the liquid nitrogen tank. Here it
can be safely stored for long periods of time, since
biological activity practically stops at liquid nitrogen
temperatures (-320F). Semen is generally to be used
within 6 months, but conceptions have resulted from
semen stored for several years, although sperm survival
is decreased, resulting in lower conception rates.
13. Semen Collection Bucks are
handled basically the same way as bulls for semen
collection. Three basic methods may be employed, but
all three require an artificial vagina, a double walled
device with an opening at one end and collection tube
at the other. The inner lining holding warm water
should be coated with a light application of water
soluble lubricating jelly. The three methods are:
1) A buck may be allowed to mount a doe, with the
semen collector manually diverting the buck's penis
into the artificial vagina (ram or dog size). Don't
touch the penis directly, instead direct the penis
into the artificial vagina by grasping the buck's
sheath. After ejaculation (usually 0.5 to 1.0 cc)
has occurred, remove the artificial vagina and tip
it so that the semen will all run into the collection
tube. This method may require practice and adjustment
by both the buck and the collector before good samples
are collected.
2) A buck is trained to mount a dummy instead of a
live doe. The same procedures are followed for sample
collection. Mounting may be facilitated by applying
vaginal mucus scrapings of a doe that is in heat to
the dummy, at least during the training process.
3) Use of electro-ejaculation. The buck is not required
to mount an object, although an artificial vagina
should still be used for semen collection. An electrode
unit, which has a number of contact rings, is inserted
into the buck's rectum. Slight electric stimulation
brings on ejaculation. This technique generally results
in good samples in quantity and quality. However,
the sperm concentration of the sample will be lower.
This method does not require extensive training, and
will allow collections from bucks that may refuse
or are unable to mount and serve an artificial vagina.
14. Semen, once collected, may
be used in one of three different ways:
1) As liquid semen, directly or on the same day one
ejaculate can serve 3 to 5 does. If kept at body temperature,
the semen may be good for three hours.
2) Semen may be stored 24 to 48 hours by placing the
collection tube in a container of water and putting
this unit in a refrigerator. No diluter is needed,
although plain egg yolk can serve as simple extender
to double the number of does that can be served.
3) Semen that is to be stored for longer periods of
time must be mixed with a diluter and very carefully
frozen. A commercially prepared diluter extender,
such as Ortho Semen Diluter is desirable, although
plain milk can be used successfully also. Following
are steps in semen extending:
a) with a commercial preparation, use a diluter to
semen ratio of 19:1, adding the semen to the diluter,
and rolling the bottle gently to achieve a thorough
mixing. The semen and diluter should be at the same
temperature. This mixture can be stored in the refrigerator
and used for a week, or slowly cooled and stepwise
frozen for storage in a liquid nitrogen tank for later
insemination.
b) for a homemade milk diluter, it is best to use
fresh 3.5 pasteurized, homogenized whole milk. It
must be heated and held at 210F for 10 minutes in
a glass boiler, keep the lid in place so that no moisture
is lost. Next, the milk is cooled in a water bath
with the lid on. When the milk is in equilibrium temperature
with the water bath, the water condensation on the
inside of the lid is shaken back into the milk. To
every 400 cc of milk, add 100,000 units of potassium
G crystalline penicillin and 500 mg crystallin di-hydrostreptomycin
sulfate, mixing well. Warm this diluter to about body
temperature before adding the fresh semen at 19:1
ratio. Place the diluted semen in a water bath at
body temperature of 101F and allow to cool slowly.
Semen may be frozen, if the extender contains an antifreeze
compound, slowly, stepwise for storage on dry ice
or in liquid nitrogen.
15. A microscope, capable of
900x magnification is an essential tool when doing
your own semen collection in order to determine semen
quantity and quality. First, place a semen sample
on a clean slide and cover with a coverslip or another
slide. Set the magnification to 400x and observe the
appearance of dark patches or spots thru the scope;
four dark areas or more per microscope field represent
high concentrations of sperm, a really good sample.
Three dark areas is somewhat chancy for use at a diluted
service, but is good enough for natural service. Two
dark areas should be used only for natural services
and one dark area means that the concentration of
sperm is too low for even natural service.
16. Switching to 900x, the sperm
cells can be individually observed for normal structures.
Diluting in warm saline is helpful. Coiled tails,
broken tails, absence of tails and abnormal shapes
all constitute deficient sperm cells. Sixty to 70
motility before freezin should be observed in a good
sample, with a minimum of 30motility after freezing
and thawing. Any insemination program, no matter how
carefully carried out, will yield poor results if
the concentration and quality of the collected sperm
is not of high standards. Sophisticated techniques
of washing the sperm free of seminal plasma before
extending and freezing will improve post-thaw viability.
17. The concentration of a buck
semen ejaculate can be determined accurately by using
a red blood cell diluting pipette and standard hemocytometer
techniques. Typical results during the breeding season
are 3 to 5 billion sperm per cc. Optical density can
also be used to estimate sperm concentration if the
photometer has been calibrated for buck semen. A simpler
technique involves the determination of a spermatocrit
using microhematocrit pipettes. The aliquot of semen
is centrifuged for 10 minutes; for each percentage
point of packed sperm, approximately 200 million sperm
cells per cc are present. Correction is made for the
percent motile sperm, after which the ejaculate can
be diluted appropriately to supply a minimum of 125
million motile sperm in each breeding dose. It is
often difficult to introduce more than 0.2 ml of semen
into the cervix, so dilution to a final concentration
of 600 million to 1.2 billion live sperm per cc has
been recommended. When no laboratory support is available,
fresh semen for immediate use may be diluted up to
5 times in extender if it is yellowish and 10 times
if the ejaculate is white. A straw holding 0.5 cc
of this diluted semen will provide adequate sperm
if excessive reflux does not occur.
18. Storage and Removal of Semen
from the Liquid Nitrogen Tank A liquid nitrogen tank
is basically a very large thermos-bottle in which
liquid nitrogen is placed to keep the inner temperature
near -320F (-196C). The spacing between the inner
and outer walls is insulated and under vacuum. The
temperature in the tank is maintained uniformly at
-320F up to the bottom of the tank neck until the
liquid nitrogen level gets down to around 5''. To
measure liquid nitrogen, use a piece of black metal
rod that is long enough to hold and touch the bottom
of the tank. Dip the rod to the tank bottom and remove
after 30 seconds. By waving it in the air, a white
frost line will appear on the rod. This line indicates
the liquid nitrogen depth of the tank. Levels nearing
5'' require a refill. The only real differences between
tanks is their storage capacity (number of ampules
or straws that they will hold) and their length of
holding time (liquid nitrogen evaporation rate). The
neck diameter varies somewhat also, with wider openings
being easier to work with, but an increased evaporation
rate usually results.
19. When working with semen in
the liquid nitrogen tank, it is important to keep
the racks below the frost line in the neck of the
tank. Removal of semen from the tank for periods as
brief as 10 seconds, such as for identification, before
replacing it to the tank will often result in lowered
fertility levels. If the right rack can't be located
in 5 seconds, lower the canister back to the bottom
of the tank for at least 30 seconds before trying
again. Also, when handling semen, try to stay out
of any direct sunlight, as ultraviolet light has a
spermicidial effect.
20. The semen comes in two basic
types of packaging: ampules (1 ml) and straws (0.5
or 0.25 ml). The ampule is the most common type of
packaging for buck sperm. Both ampules and straws
are stored in racks (canes), which are aluminum pieces
that hold a vertical row of ampules, usually six,
or two g ++++MISSING DATA++++
21. A few key reminders concerning
semen storage:
1) Always keep the liquid nitrogen level above 5''.
2) Never lift a canister above the frost line of the
tank.
3) When the semen is removed with a forceps from the
tank it should be placed immediately in the thaw box.
4) Never expose semen to direct ultraviolet light.
5) Never refreeze semen that has been thawed as it
will be destroyed.
6) Check for proper identification on ampule or straw.
7) A defective ampule may blow up after it is removed
from the tank. This is due to a small leak that allows
nitrogen to enter the ampule. When removed from the
tank, the gas expands too rapidly to vent back out
the hole and it explodes the glass. A hissing sound
is usually audible when it is removed. Keep your hand
between the ampule and your face when putting it into
thaw box.
8) Always wear gloves and goggles for your own protection
when working inside a liquid nitrogen tank.
22. Thawing Procedures Methods
for semen thawing vary among manufacturers, and it
is best to follow their recommendation. The thawing
procedure for 1cc ampules, the most common for goat
semen, is generally the ice water bath:
1) Ice water (38-42F) is placed in a styrofoam box
long enough before-hand to allow temperature to equilibrate.
2) Remove the ampule from tank and place immediately
into thaw box. Ampule may be placed in a small plastic
cup with holes in the bottom. This prevents ice from
coming into direct contact with ampule.
3) Ampule should thaw in 3 to 5 minutes. Check for
slushiness and allow more time if needed.
4) Ampule may sit in ice water for as long as 30 minutes
with no damage. Once removed, the semen must be used
right away.
5) The layer of ice on the ampule must be peeled off
before opening to avoid possible contamination.
23. The ice water thaw method
is especially good during winter breeding of does
because of low risk of cold shock to thawed and exposed
semen. Thawing of semen can be done from -320F rapidly,
but any subsequent exposure to lower temperatures
after thawing will kill many or all of the sperm.
24. The warm water method of
thawing is more exact than the ice water method, but
probably will not work in cold weather, although it
may give somewhat better results the rest of the year.
The procedure is basically the same as for the ice
water thaw except that:
1) The water must be maintained at 92 to 98F. This
requires a source of warm water and an accurate thermometer.
2) Thawing will be complete in about 1 minute with
no ice layer formation of the ampule.
3) Ampules thawed with the warm water method should
be used within 5 minutes.
25. Straws (0.5 or 0.25 ml) can
be thawed by either of the previous two methods. A
given amount of semen in a straw will take about one
half as long to thaw as an equal amount in an ampule.
Many inseminators simply thaw straws by placing them
into their shirt or pants pocket.
26. Inseminating Procedures All
the care in handling, storage and preparation of semen
will be useless if the inseminating process is not
done carefully and cleanly. Hygienic practices at
this point cannot be over-emphasized. All reusable
items such as inseminating guns (for straws), scissors
for cutting straws, scribe for cutting ampules, etc.
must be wiped clean with 70 0sopropyl alcohol and
allowed to dry before reuse. Disposable items should
be kept in their sealed packages until they are to
be used. The speculum should be sterilized after each
use (this is one reason why the cattle industry discontinued
the speculum method; the inseminator would have to
carry a few dozen specula on his daily rounds, sterilizing
them each night). This is best accomplished by boiling
for 10 minutes, allowing to air dry. Then place inside
a sterile container or wrapping, such as a new plastic
AI glove. Disposable plastic type specula for goats
can be obtained from mail order companies, eliminating
the need for constant resterilization.
27. Materials needed for artificial
insemination:
1) Speculum, Pyrex 22 x 175 mm for doelings; 25 x
200 mm for adult does; or stainless steel human vaginal
speculum; or plastic disposables; with a small clip-on
flashlight.
2) Sterile lubricating jelly (K-Y)
3) Thaw box
4) a. Inseminating pipette with bulb or syringe (ampules
only) or b. Inseminating gun (straws only)
5) Paper towels
6) Facility for securing doe (stanchion, fence, rope
hoist)
7) Recording journal for breeding dates, buck's name,
etc.
28. Preparing Ampules:
1) Partially remove an inseminating pipette from its
plastic bag.
2) Place bulb or syringe on exposed end.
3) Thaw ampule according to the described methods.
4) Dry ampule after thawing, hold in paper towel and
scribe (with proper tool) one side of ampule collar.
Some ampule types do not need to be scribed, but can
be snapped open.
5) Pull syringe back 1/2 cc on plunger or squeeze
bulb closed before placing pipette into ampule.
6) Tip ampule to slight angle and maintain constant
suction on pipette while it is slowly inserted into
the ampule. Try to get all the semen into the pipette,
keeping the semen column down near the end of the
pipette.
7) When filled, the pipette should have a semen column
with no air spaces, with the bottom of the column
being 1 to 2'' from the pipette tip. Do not draw semen
into the syringe or bulb.
8) Keep the ampule for information to complete breeding
records.
9) Keep the pipette away from sunlight or cover with
paper towels.
10) The semen is now ready to be placed into the doe
in estrus.
29. Preparing Straws:
1) An inseminating gun, designed for your type of
straw is needed, obtainable thru farm supply houses
or the local cattle AI technician. Have cover sheath
available, sealed until needed.
2) Place straw in thaw box.
3) Remove when thawed, wipe dry. Check buck information.
4) Pull plunger on gun back 4 to 6'' and insert straw
into gun, cotton plug end first (towards plunger).
5) Hold gun in upright position, allowing air bubble
to rise to the sealed end.
6) Cut sealed end of straw with scissors. Take care
to cut straw squarely for proper seating.
7) Install the sheath over the gun, fastening it down
with the provided O-ring. Install it so that the wider
side of the ring faces the straw, with the narrower
side facing the syringe end.
30. Insemination: Assuming that
the doe has been observed in heat, has been suitably
restrained (i.e. in stanchion) and the steps for preparing
the ampule or straw have been followed. The next steps
are:
1) Position doe on milk stand. The inseminator places
his left foot on the stand and drapes the hindquarters
of the goat across his horizontally positioned thigh.
The goat is allowed to stand as long as she does not
struggle or collapse. The vulva is cleaned.
2) Hold pipette or inseminating gun, wrapped in a
paper towl, in your mouth; or let someone else hold
it if extra hands are available.
3) Turn head light on and insert lubricated speculum
in a slow and gentle manner. Begin entrance at a somewhat
upward angle for the first several inches. This is
to prevent the speculum from scraping across the vaginal
floor, possibly doing damage to the urethral opening.
4) Complete insertion of speculum and locate cervix.
Center the end of the speculum over the os uteri (entrance
to cervical canal).
5) Cervix should be of a red-purple coloration with
a viscous whitish mucus present if doe is truly in
heat.
6) Insert pipette or inseminating gun into speculum
to the cervix. Gently manipulate the instrument through
the cervical canal (cervix is 1 to 2'' long) to the
4th or 5th annular ring.
7) Deposit semen near the uterine end of the cervix
or just inside the uterus. Do not enter too far into
the uterus as the semen will then tend to be dumped
into one horn or the other. If the semen is pushed
into the wrong horn (i.e. egg produced in left ovary,
semen dumped into right horn) then fertilization may
not occur.
8) Deposit semen slowly, taking at least five seconds.
9) Slowly withdraw instrument without release of syringe
or depressed bulb, then carefully remove the speculum.
10) Record all pertinent breeding information.
11) Carefully discard all disposable materials. Arrange
to sanitize reuseable items and sterilize the speculum
(if it is a non-disposable type).
31. Frequently, the pipette cannot
be passed all the way through the cervix even though
the doe is in heat. If it has penetrated deeply into
the cervix (3 to 4 cm, as determined by laying another
pipette alongside the first and observing the distance
by which the outer ends are offset), cervical insemination
will provide a conception rate almost equal to that
of intrauterine semen deposition. The conception rate
expected from intra-vaginal insemination, however,
is less than 30 If semen is very valuable, it may
be advisable to pass a trial pipette to determine
patency of the cervix before thawing the semen unit.
32 In France, a doe is usually restrained by a second
person who straddles the doe's neck and elevates the
hindquarters to a vertical position while holding
the hind limbs tightly flexed. The inseminator is
free to stand in a comfortable position. He holds
the speculum and the goat's tail in one hand and the
pipette or straw gun in the other hand. If excess
mucus is a problem, the assistant lowers the goat's
hindquarters almost to the ground; if the mucus does
not run out of the speculum, the latter is removed
and shaken to clear it. The goat is then lifted to
its former position. If many goats are to be bred,
the assistant may tire using this technique. If the
doe is not held in a vertical position, it is often
impossible to adequately visualize and penetrate the
cervix. Various slings have been devised to suspend
the goat in the appropriate position.
